Connecting sheet metal end sections by means of forming

ABSTRACT

In one embodiment, the method includes providing a double sheet metal element including the two sheet metal end sections; and creating a connecting section along the connecting line. The creation of the connecting section includes introducing a first depression into the double sheet metal element, and creating a first folded section of the double sheet metal element. The method further includes orienting the connecting section relative to an extension plane of the double sheet metal element so that the connecting section extends perpendicularly to the extension plane.

The invention relates to a method and to a device for connecting twosheet metal end sections arranged on top of one another.

Welding methods, for example, are known for connecting sheet metal.Using such a welding method, however, can result in shrinkage, highinternal stress, and structural changes in the seam region of the sheetmetal to be connected. In the process, there is a risk that brittlefracture tendency as well as cracking may occur in the seam region.

In the case of thin sheet metal, it is furthermore customary to connectthe sheet metal by way of spot welding. In the case of uneven sheetmetal or in the presence of additional foreign material, for examplefrom coatings, particles of which can find their way into the weld spot,there is an increased risk that faulty welds can occur. In the case of awelding process, additionally in general the need arises to provide anysharp-edged sheet metal edges that remain after the welding process withadditional edge protection, or to additionally fold these over in afurther processing step, to avoid a risk of injury.

It is the object of the invention to create an improved method forconnecting two sheet metal end sections.

The object underlying the invention is achieved by the features of theindependent claims. Embodiments of the invention are described in thedependent claims.

Embodiments include a method for connecting two sheet metal end sectionsarranged on top of one another by means of forming. The method comprisesproviding a double sheet metal element, which includes the two sheetmetal end sections arranged on top of one another and extends in anextension plane. This extension plane denotes a plane in which the twosheet metal end sections jointly extend prior to a connecting sectionbeing created. The two sheet metal end sections are to be connected toone another along a connecting line located in the extension plane.According to embodiments, the connecting line extends parallel to anedge of the double sheet metal element. A connecting section is createdalong the connecting line. The creation of the connecting sectionincludes introducing a first depression extending along the connectingline, for example a V-shaped depression, into the double sheet metalelement. A first folded section of the double sheet metal element iscreated along the connecting line, wherein two mutually opposing insidewalls of the first depression are pressed against one another. The firstdepression is closed by pressing the inside walls against one another.According to embodiments, only a narrow gap remains between the twoinside walls that are pressed against one another. The first foldedsection is thus a section that is folded once.

The connecting section, which includes the first folded section, isoriented perpendicularly relative to the extension plane of the doublesheet metal element by bending a portion of the double sheet metalelement which includes the connecting section along a first bending axisextending parallel to the connecting line, so that the first foldedsection or connecting section extends perpendicularly to the extensionplane. For example, the connecting section can be implemented by thefirst folded section, that is, a section folded once. It is possible,for example, for more than one fold to take place, and for theconnecting section to be implemented by a section that is foldedmultiple times, for example folded twice.

Embodiments can have the advantage that a method for quickly andreliably connecting two sheet metal end sections is provided, which, forexample, is able to replace conventional welding processes. The methodis characterized by high stability, reliability, speed, and a low needfor maintenance. For example, the method for connecting provided hereprevents sharp edges from being created or remaining. Embodiments canhave the advantage that the resulting connecting section ischaracterized by small dimensions and, in particular, has a smallextension parallel to the original extension plane compared to the twosheet metal end sections prior to the use of the method. The methodmakes it possible to use fully automated systems for connecting thesheet metal end sections, which allow processing times in the range of afew seconds. For example, processing times of less than three secondsper double sheet metal element can be achieved in this way. According toembodiments, the portion of the double sheet metal element including theconnecting section, as a result of the perpendicular orientation, onlyhas a small extension, proceeding from the first bending axis, parallelto the original extension plane of the double sheet metal element of afew millimeters. For example, the extension is less than 4 mm or lessthan 3 mm. According to embodiments, the connecting section has a widthof the same size.

According to embodiments, the creation of the connecting sectionfurthermore includes introducing a second depression extending along theconnecting line, for example a V-shaped depression, into the doublesheet metal element. A second folded section of the double sheet metalelement along the connecting line is created, wherein two mutuallyopposing inside walls of the second depression are pressed against oneanother, and the second folded section encompasses the first foldedsection. The second folded section is thus a section that is foldedtwice. The second depression is closed by pressing the inside wallsagainst one another. According to embodiments, only a narrow gap remainsbetween the two inside walls that are pressed against one another. Inthis embodiment, the connecting section is implemented by the secondfolded section, that is, a section that is folded twice.

Embodiments can have the advantage that, as a result of the multiple,for example double, folding and the resulting specific shape, the secondfolded section of the double sheet metal element, and thus theconnection between the two sheet metal end sections provided by theresulting connecting section, is highly stable.

According to embodiments, the connecting section is the second foldedsection. A connecting section comprising the first and second foldedsections, that is, which is folded twice, is created, for example, alonga straight edge of the double sheet metal element. As a result of thedouble fold, very high stability of the connection may be implemented.According to embodiments, the connecting section is the first foldedsection. A connecting section that only comprises the first foldedsection, that is, which is folded once, is created, for example, along acurved edge of the double sheet metal element. Along a curved edge, thatis, on a bent curve track, a single fold can have the advantage ofeasier processing, for example due to a lesser degree of internalmaterial stresses, while offering sufficient stability of theconnection.

According to embodiments, the two sheet metal end sections of the doublesheet metal element which are arranged on top of one another have thesame length, that is, proceeding from the connecting line, the two sheetmetal end sections extend equally far along the shared extension plane,or the edges of the two sheet metal end sections are arranged on top ofone another. Together, the two edges form the edge of the double sheetmetal element. In this case, the two sheet metal end sections contributeequally to the creation of the first depression. According toembodiments, the two sheet metal end sections of the double sheet metalelement which are arranged on top of one another have differing lengths,that is, proceeding from the connecting line, the two sheet metal endsections extend differently far along the shared extension plane. Inthis case, the edges of the two sheet metal end sections are arrangedoffset with respect to one another, and the edge of the double sheetmetal element is formed by the edge of the sheet metal end sectionextending further along the extension plane. In this case, the two sheetmetal end sections contribute to the creation of the first depression todifferent degrees. For example, one of the two sheet metal end sectionsdoes not extend to a base of the first depression and/or does not extendbeyond the base. In this case, the edge of this sheet metal section iseither enveloped by the second sheet metal section when the first foldedsection is created and/or is folded over when the second folded sectionis created.

A connecting line here shall be understood to mean a line, for example,a straight line or a bent curve track, along which a connection isestablished between the two sheet metal end sections. A connectingsection shall be understood to mean a section of a double sheet metalelement extending along a connecting line, in which the two sheet metalend sections of the double sheet metal element are connected to oneanother by means of forming, that is, a section of a double sheet metalelement in which the forming step was carried out.

According to embodiments, the method comprises aligning the connectingsection, prior to the perpendicular orientation of the connectingsection. The alignment of the connecting section comprises bending theconnecting section about a second bending axis extending parallel to theconnecting line, so that the connecting section extends parallel to theextension plane of the double sheet metal element. Embodiments can havethe advantage that the alignment of the connecting section makes iteasier to perpendicularly orient the connecting section.

According to embodiments, the connecting section is the second foldedsection, and the method comprises aligning the second folded section,prior to perpendicularly orienting the second folded section. Thealignment of the second folded section comprises bending the secondfolded section about a second bending axis provided by an edge of thesecond depression, so that the second folded section extends parallel tothe extension plane of the double sheet metal element.

According to embodiments, the double sheet metal element comprises anedge, which provides a free end of the double sheet metal element. Theconnecting line, along which the two sheet metal end sections are to beconnected to one another, extends, for example, parallel to this edge.By carrying out the above-described method for connecting two sheetmetal end sections that are arranged on top of one another, the free endof the double sheet metal element is folded over twice andperpendicularly oriented.

According to embodiments, each of the two sheet metal end sections is anedge section of two parts to be connected to one another. For example,the two parts to be connected to one another are two half shell elementsor two hollow body halves. According to embodiments, the two parts canbe two halves of a vehicle catalytic converter casing, for example.

Sheet metal here shall be understood to mean a flat finished rollingmill product made of metal, for example stainless steel. The sheet metalcan furthermore comprise additional material layers, such as coatings.The additional material layers can comprise metal layers and/ornon-metal layers. The sheet metal can have a planar surface or aprofiled surface, for example a corrugated surface, a nubby surfacehaving a groove pattern and/or a surface provided with a honeycombpattern.

According to embodiments, each of the two sheet metal end sections hasan edge, wherein the two edges of the sheet metal end sections arrangedon top of one another extend parallel to one another. For example,proceeding from the two edges, the two sheet metal end sections of thedouble sheet metal element which are arranged on top of one anotherextend parallel to one another in the same direction. According toembodiments, the two edges of the two sheet metal end sections arrangedon top of one another extend parallel to an edge of the double sheetmetal element. According to embodiments, the edge of the double sheetmetal element is provided by one or both edges of the two sheet metalend sections arranged on top of one another.

A folded section of the double sheet metal element here shall beunderstood to mean a section of the double sheet metal element thatcomprises at least two sub-sections of the double sheet metal elementwhich are arranged on top of one another as a result of a fold, that is,a bend by 180° along a bending axis.

According to embodiments, the double sheet metal element comprises afree end, which is a freely movable end within the scope of thebendability of the two sheet metal end sections. According toembodiments, the double sheet metal element furthermore comprises afixed end, which extends, for example, parallel to the free end.According to embodiments, the fixed end is at least intermittently fixedso as to be immovable. According to further embodiments, the fixed endis fixed in such a way that only movements parallel to the connectingline are made possible. According to embodiments, the fixed end, forfixation, is clamped into a clamping device, which comprises twoclamping elements, for example, each having a clamping surface.

According to embodiments, an edge of the first depression is formed byan edge of the double sheet metal element. Embodiments can have theadvantage that they enable a compact connection between the two sheetmetal end sections of the double sheet metal element which are arrangedon top of one another. In this way, the distance between the firstdepression and the edge of the double sheet metal element can beminimized. In the process, the first depression extends parallel alongthe edge of the double sheet metal element.

According to embodiments, a first of the two mutually opposing insidewalls of the second depression is at least partially provided by thefirst folded section. According to embodiments, the first of the twomutually opposing inside walls of the second depression comprises theedge of the double sheet metal element. The edge of the double sheetmetal element was folded, for example, as a result of the free end ofthe double sheet metal element being folded over on the surface thereof.As a result of this folding, it can be prevented that a sharp edgeencompassed by the edge of the double sheet metal element remains, afterthe two sheet metal end sections have been connected.

According to embodiments, the first and second depressions are bothintroduced into a first surface of the double sheet metal element.

According to embodiments, the creation of the connecting sectionfurthermore comprises introducing a third depression extending along theconnecting line, for example a V-shaped depression, into a secondsurface of the double sheet metal element which faces away from thefirst surface, wherein the first bending axis extends along a base ofthe third depression. Embodiments can have the advantage that the thirddepression makes it easier to perpendicularly orient the second foldedsection or connecting section.

According to embodiments, the creation of the connecting sectionfurthermore comprises introducing a fourth depression extending alongthe connecting line, for example a V-shaped depression, into the firstsurface of the double sheet metal element, wherein an edge of the fourthdepression provides the first bending axis. Embodiments can have theadvantage that the fourth depression makes it easier to perpendicularlyorient the second folded section or connecting section.

According to embodiments, the creation of the connecting sectionfurthermore comprises aligning the first folded section, prior tointroducing the second depression. The alignment of the first foldedsection comprises bending the first folded section about a third bendingaxis provided by an edge of the first depression, so that the firstfolded section extends parallel to the extension plane of the doublesheet metal element. Embodiments can have the advantage that thealignment of the first folded section makes it easier to introduce thesecond depression.

A depression here shall be understood to mean a forming of a section ofthe double sheet metal element, wherein at least a portion of the formedsection relative to the extension plane of the double sheet metalelement is located lower prior to being formed and comprises a flat endsection, which extends on the same plane as a base, or a lowest regionof the depression (stepped configuration), or which, proceeding from thebase, extends in the direction of the (original) extension plane of thedouble sheet metal element. In the latter case, the flat end sectionends in a plane between the plane of the base and the extension plane,in the extension plane, or in a plane above the extension plane. Thedepression extending along the connecting line has an elongatedstretched configuration, that is, the base of the depression extendingalong the connecting line has an elongated stretched configuration.

According to embodiments, the first, second, third and/or fourthdepressions are V-shaped depressions. A V-shaped depression here shallbe understood to mean a depression that has a V-shaped cross-sectionperpendicular to a longitudinal extension direction of the depression.The V-shaped cross-section comprises at least two legs, which intersectat an angle of greater than 0° and smaller than 180°. The two legs areprovided by two mutually opposing inside walls of the V-shapeddepression. The two mutually opposing inside walls of the V-shapeddepression can be planar or arched. According to embodiments, theV-shaped depression includes a base, which can be provided in the formof an intersecting line of the two inside walls or of a connectingsurface between the two mutually opposing inside walls. The connectingsurface can be planar or arched.

According to alternative embodiments, the first, second, third and/orfourth depressions are U-shaped depressions. A U-shaped depression hereshall be understood to mean a depression that has a U-shapedcross-section perpendicular to a longitudinal extension direction of thedepression. The U-shaped cross-section includes at least two legsextending parallel to one another. The two legs are provided by twomutually opposing inside walls of the U-shaped depression. The twomutually opposing inside walls of the U-shaped depression can be planaror arched. According to embodiments, the U-shaped depression includes abase, which can be provided in the form of a connecting surface betweenthe two mutually opposing inside walls. The connecting surface can beplanar or arched.

According to alternative embodiments, the first, second, third and/orfourth depressions are steps. A step includes a first step surface,which has a longitudinal extension direction along the longitudinalextension direction of the depression. According to embodiments, thefirst step surface extends parallel to the extension plane of the doublesheet metal element. According to embodiments, the first step surfaceincludes an angle of greater than or equal to 0° and smaller than 90°with the extension plane of the double sheet metal element. A stepfurthermore includes a second step surface, which connects the firststep surface to the extension plane of the double sheet metal elementand has a longitudinal extension direction along the longitudinalextension direction of the depression. According to further embodiments,the second step surface includes an angle of greater than 0° and smallerthan or equal to 180° with the extension plane of the double sheet metalelement. According to embodiments, the first step surface extendsparallel to the extension plane of the double sheet metal element, whilethe second step surface extends perpendicularly to the first stepsurface and the extension plane of the double sheet metal element.

According to embodiments, the method furthermore comprises positioningand fixing the double sheet metal element in a processing position. Thepositioning of the double sheet metal element in the processing positiontakes place by introducing the first depression by means of a devicethat engages with the double sheet metal element. The fixation of thedouble sheet metal element in the processing position takes place usinga clamping device, wherein the double sheet metal element, when thedouble sheet metal element is clamped by means of the clamping device,is held in the processing position by the device having engaged with thedouble sheet metal element.

Embodiments can have the advantage that the length of the double sheetmetal element parallel to the extension plane is shortened by theintroduction of the first depression. In this way, the double sheetmetal element as well as sheet metal sections that adjoin the sheetmetal end sections are pulled to the device engaging with the doublesheet metal element, which introduces the first depression. The doublesheet metal element is thus positioned for further processing in aprocessing position. To be able to pull the double sheet metal elementand/or the adjoining sheet metal sections to the engaging device, suchas a punch and/or a die, the freedom of movement thereof, in particularin the direction of the corresponding device, is initially notrestricted. The clamping device, which fixes the position of the doublesheet metal element during further processing, only clamps the doublesheet metal element after the device for introducing the firstdepression has engaged with the double sheet metal element. The clampingdevice comprises, for example, two clamping elements, which each includea clamping surface. The two clamping surfaces face one another, forexample, and are arranged on top of one another. Furthermore, the twoclamping surfaces extend parallel to the extension plane of the doublesheet metal element. One of the clamping surfaces forms part of abearing surface, for example, on which the double sheet metal elementrests for processing. A position of the double sheet metal element canbe fixed in that at least one of the clamping elements moves toward theother, and the distance between the two clamping surfaces decreases.According to alternative embodiments, the clamping device only comprisesone independent clamping element, while the second clamping element isprovided by a die, which is additionally used to introduce one or moredepressions into the double sheet metal element.

A respective curved sheet metal section, for example a half shellsection, adjoins the two sheet metal end sections, for example. The twocurved sheet metal end sections include an angle, for example, whichincreases with increasing distance from the two sheet metal end sectionsuntil it has reached a maximum value. The corresponding angle can beformed, for example, by the tangents to the curved sheet metal sections.

According to embodiments, the clamping device is arranged between thedevice for introducing the first depression and the curved sheet metalsections when the double sheet metal element and/or the curved sheetmetal sections are located in a starting position. If the firstdepression is introduced without the double sheet metal element beingfixed by the clamping device, the curved sheet metal sections, forexample half shell sections, are pulled to the device for introducingthe first depression, and a fixation by the clamping device only occursin this processing position. According to embodiments, this results inthe curved sections being automatically positioned flush on the clampingdevice or at least partially between the two clamping surfaces. Clampingby means of the clamping device causes sheet metal sections arrangedbetween the clamping surfaces to be pressed flat against one another. Ifcurved sheet metal sections, such as curved sheet metal sections havinga small curvature, that is, a small included angle, are arranged betweenthe clamping surfaces, this angle is closed, and the remaining curvedsheet metal sections adjoining the closed region have a larger remainingangle than the closed angle.

Embodiments can have the advantage that, during clamping, the curvedsheet metal sections cannot be pushed out of the region between the twoclamping surfaces due to the curvatures and the resulting horizontalforce components. Rather, this is suppressed by the device havingengaged with the double sheet metal element. By suppressing the curvedsheet metal sections from being pushed laterally out of the regionbetween the clamping surfaces, damage to structures that enclose thesheet metal sections can be prevented.

Corresponding structures may, for example, be insulating material and/orelements of a vehicle catalytic converter.

Embodiments can have the advantage that the resulting distance betweenthe perpendicularly oriented connecting section and the remaining curvedsheet metal sections can be reduced to a width of the clamping surfaces.

Curved sheet metal sections that adjoin the sheet metal end sections arecreated, for example, by deep drawing a planar metal sheet, using apositive mold. So as to prevent damage as a result of the deep drawingprocess, the curved sheet metal sections at the beginning, that is,directly adjoining the sheet metal end sections, initially have a smallcurvature, for example. The small curvature results in a small distancebetween curved sheet metal sections when these are arranged on top ofone another in such a way that the curvatures are oriented in oppositedirections and enclose a hollow space. For example, two half shellelements are positioned on top of one another so as to enclose a hollowspace for receiving additional structures. The sheet metal sectionshaving a small curvature represent lost space, since no additionalstructures can be arranged between these due to the small distance, suchas insulating material and/or catalytic converter elements. Rather, thesheet metal sections having a small curvature can have the disadvantageof unnecessarily increasing the overall size or the diameter of thedouble sheet metal element parallel to the extension plane. By pullingthe sheet metal sections having a small curvature between the clampingsurfaces of the clamping device and clamping the corresponding sheetmetal sections together, it can be achieved that these establish thedistance between the perpendicularly oriented connecting section and theremaining curved sheet metal sections, which corresponds to the width ofthe clamping surfaces. Otherwise, the distance would include thecorresponding sheet metal sections having a small curvature, in additionto the width of the clamping surfaces, and could end up beingconsiderably larger, for example twice as large.

According to embodiments, the method furthermore comprises introducing acorrugated structure having a plurality of additional depressions intothe connecting section, wherein the additional depressions, when theconnecting section is oriented perpendicularly, extend perpendicularlyto the extension plane.

Embodiments can have the advantage that the corrugated structureincreases theholding force of the connection between the two sheet metalend sections. By introducing the corrugated structure, it is thuspossible to reduce the likelihood for the connection between the twosheet metal end sections which is implemented by the connecting sectionto detach under load. Rather, as a result of the corrugated structure,the stability of the connecting section can be increased. According toembodiments, a corresponding corrugated structure can be introduced bothinto a connecting section that extends along a straight connecting line,and thus a straight first bending axis, and into a connecting sectionthat extends along a curved connecting line, and thus a curved firstbending axis.

According to embodiments, the additional depressions each have a depththat increases with increasing distance from the extension plane.Embodiments can have the advantage that an arc length of the connectingsection, which increases with the distance from the bending axis, can beeffectively compensated for by a corresponding variation of the depth ofthe additional depressions in the case of a curved connecting line or acurved first bending axis. This applies in particular in the case of aconvex curvature. Using a corrugated structure having an accordinglyvarying depth, it is possible to accommodate oversized lengths of theconnecting section in a compact manner during the perpendicularorientation.

According to embodiments, the method furthermore comprises introducing aplurality of recesses into the double sheet metal element along thefirst bending axis, wherein each of the recesses extends from the firstbending axis to the edge of the double sheet metal element. Embodimentscan have the advantage that an arc length of the double sheet metalelement, which varies with the distance from the bending axis, can becompensated for by the recesses in the case of a curved connecting lineor a curved first bending axis. In the case of a convex curvature, therecesses are used to remove material that would be excess material as aresult of the perpendicular orientation of the portion of the doublesheet metal element which is folded to yield the connecting section, andof the accompanying decrease in the arc length. In the case of a concavecurvature, the recesses, by diverging, are used to compensate for an arclength increasing as a result of the perpendicular orientation of theportion of the double sheet metal element which is folded to yield theconnecting section.

According to embodiments, each of the recesses has a width thatincreases with increasing distance from the first bending axis. In thecase of a convex curvature, the perpendicular orientation of theconnecting section results in a decrease in the arc length of theconnecting section to yield a uniform size. Embodiments can have theadvantage that, as a result of the width varying with the distance, itis possible to effectively take into account the arc length of thedouble sheet metal element or of the connecting section varying with thedistance prior to the perpendicular orientation. For example, each ofthe recesses has a V shape.

In the case of a concave curvature, each of the recesses, for example,has a width that does not change with increasing distance from the firstbending axis, but rather remains constant. According to embodiments, therecesses are linear notches.

According to embodiments, the two sheet metal end sections are differentend sections of one sheet, that is, one sheet is bent in such a way thattwo end sections of the same sheet are arranged on top of one another.Embodiments can have the advantage that two sheet metal end sections canbe efficiently connected to one another. For example, the shared sheetis rolled in, thereby forming a cylinder and the two end sections of thesheet being arranged on top of one another.

According to embodiments, the two sheet metal end sections are endsections of two different sheets. Embodiments can have the advantagethat they allow two different sheets, which, for example, form two halfshell elements, to be connected to one another along the two sheet metalend sections.

According to embodiments, movable device elements of a device forconnecting by means of forming, which are involved in the course of themethod for connecting the two sheet metal end sections arranged on topof one another by means of forming, are exclusively displacedperpendicularly to the extension plane of the double sheet metalelement. In this way, no displacement parallel to the extension plane ofthe double sheet metal element takes place.

Embodiments encompass a device for connecting two sheet metal endsections arranged on top of one another by means of forming according toany one of the preceding claims. According to embodiments, the device isconfigured to carry out one or more of the above-described embodimentsof the method for connecting two sheet metal end sections that arearranged on top of one another.

According to embodiments, the device comprises a plurality of rollerpairs, which carry out the individual steps of the method. According toembodiments, the roller pairs are arranged in a row behind one another,wherein the double sheet metal element is displaced along the row ofroller pairs and consecutively passes through the individual rollerpairs along the connecting line. For example, the roller pairs can bearranged in a stationary manner behind one another, and the double sheetmetal element is displaced. Embodiments can, for example, beadvantageous when the connection is to be implemented along a straightconnecting line. According to embodiments, the device is configured todisplace the roller pairs in a path-controlled manner along an edge ofthe double sheet metal element. For example, the roller pairs aredisplaced, while the double sheet metal element is arranged in astationary manner. Embodiments can, for example, be advantageous whenthe connection is to be implemented along a bent connecting line.According to further embodiments, the roller pairs and the double sheetmetal element are both displaced relative to one another.

According to embodiments, multiple of the steps of the method arecarried out by the same roller pair. For example, the introduction ofthe first and second depressions is carried out by the same roller pair.For example, the creation of the first and second folded sections iscarried out by the same roller pair. For example, the alignment of thefirst and second folded sections is carried out by the same roller pair.

According to embodiments, the device comprises a plurality of rollerpairs arranged in a row behind one another, which consecutively carryout the individual steps of the method, wherein the double sheet metalelement consecutively passes through the roller pairs along theconnecting line. According to embodiments, the double sheet metalelement is guided along the row of roller pairs and/or the devicecomprising the row of roller pairs is guided along the double sheetmetal element. According to embodiments, roller pairs can comprise ashared roller, so that this shared roller belongs to two differentroller pairs, which carry out two different method steps. According toembodiments, the rollers of the roller pairs each have a profile, whichis configured to carry out one of the steps of the above-describedmethod.

According to embodiments, the device comprises a punch and a die. Thepunch comprises one or more punch elements extending in a longitudinaldirection for introducing depressions into the double sheet metalelement. The die comprises a bearing surface for placing on the doublesheet metal element, including a plurality of cavities, which extendparallel to one another along the longitudinal direction of the punchelements and are each configured to introduce at least one of thedepressions into the double sheet metal element.

The punch is configured to be displaced in a first direction vertically,that is, from above, by way of one of the punch elements into one of thecavities for introducing the depressions. According to embodiments, thepunch is furthermore configured to be displaced in a second directionparallel to the bearing surface, and perpendicularly to the firstdirection, by way of one of the punch elements against the double sheetmetal element, for creating the folded sections and/or forperpendicularly orienting the connecting section. According toembodiments, one or more of the cavities in each case have a V-shapedcross-section for introducing V-shaped depressions into the double sheetmetal element. According to embodiments, one or more of the punchelements in each case have a V-shaped cross-section for introducingV-shaped depressions into the double sheet metal element. According toembodiments, one of the legs of the V-shaped cross-section of the punchelement is provided by a first stop surface, which is used to create atleast one of the folded sections. According to embodiments, the punchcomprises a second stop surface, which is used to perpendicularly orientthe connecting section.

According to embodiments, at least one of the cavities has a U-shapedcross-section for introducing a U-shaped depression into the doublesheet metal element, while at least one of the punch elements likewisehas a U-shaped cross-section.

According to embodiments, the punch is furthermore configured to bedisplaced in a first direction vertically by way of one of the punchelements into one of the cavities for creating the folded sections.

According to embodiments, the die is configured to be displaced in adirection that is opposite the first direction for introducing one ofthe depressions, for creating one of the folded sections and/or forperpendicularly orienting the connecting section.

According to embodiments, the die comprises a plurality of sub-dies.Together, the sub-dies provide the bearing surface for bearing surfacefor placing on the double sheet metal element. Each of the sub-diescomprises at least one of the cavities. Furthermore, at least one of thesub-dies is configured to be displaced in the direction that is oppositethe first direction for introducing one of the depressions, for creatingone of the folded sections and/or for perpendicularly orienting theconnecting section.

According to embodiments, the displaceable die and/or sub-die comprisesa stop surface, which is used to perpendicularly orient the connectingsection.

According to embodiments, the device furthermore comprises a clampingdevice for fixing the double sheet metal element in a processingposition. According to embodiments, an end of the double sheet metalelement is immovably fixed by the clamping device.

According to embodiments, the device furthermore comprises an embossingelement having a corrugated surface, which is configured to introduce acorrugated structure having a plurality of additional depressions intothe connecting section, wherein the additional depressions, in theperpendicularly orientated state of the connecting section, extendperpendicularly to the extension plane.

According to embodiments, the device furthermore comprises a cuttingdevice, which is configured to introduce recesses into the double sheetmetal element along the first bending axis, wherein the recesses in eachcase extend from the first bending axis to the edge of the double sheetmetal element.

Here, ordinal numbers such as first, second, third, fourth, and soforth, are solely used to distinguish elements that are different fromone another, and shall not be construed to imply a particular sequence,unless a meaning to the contrary follows from the specific context.Embodiments of the method can, for example, introduce a first, secondand fourth depression into the double sheet metal element, withoutnecessarily also introducing a third depression.

Embodiments of the invention will be described in more detail hereafterwith reference to the drawings. In the drawings:

FIG. 1 show schematic diagrams of exemplary embodiments of double sheetmetal elements;

FIG. 2 show schematic diagrams of exemplary embodiments of double sheetmetal elements;

FIG. 3 shows a schematic flow chart of an exemplary embodiment of afirst method;

FIG. 4 show schematic diagrams of an exemplary embodiment of a devicefor carrying out the first method from FIG. 3;

FIG. 5 show schematic diagrams of exemplary embodiments of V-shapeddeprescions;

FIG. 6 shows a schematic flow chart of an exemplary embodiment of asecond method;

FIG. 7 show schematic diagrams of an exemplary embodiment of a devicefor carrying out the second method from FIG. 6;

FIG. 8 shows a schematic flow chart of an exemplary embodiment of athird method;

FIG. 9 show schematic diagrams of an exemplary embodiment of a devicefor carrying out the third method from FIG. 8;

FIG. 10 show schematic diagrams of exemplary embodiments of elements ofthe device from FIG. 9;

FIG. 11 show schematic diagrams of exemplary embodiments of elements ofan alternative device;

FIG. 12 show schematic diagrams of exemplary embodiments of double sheetmetal elements including recesses;

FIG. 13 show schematic diagrams of exemplary embodiments of double sheetmetal elements having a corrugated structure;

FIG. 14 show schematic diagrams of exemplary embodiments of an embossingtool;

FIG. 15 shows a schematic flow chart of an exemplary embodiment of afourth method;

FIG. 16 show schematic diagrams of an exemplary embodiment of a devicefor carrying out the fourth method from FIG. 15;

FIG. 17 show schematic diagrams of an exemplary embodiment of sheetmetal end sections;

FIG. 18 shows a schematic diagram of an exemplary embodiment of a metalsheet; and

FIG. 19 show schematic diagrams of exemplary first folded sections.

Elements of the following embodiments that correspond to each other aredenoted by the same reference numerals.

FIGS. 1A to 1C show exemplary double sheet metal elements 100. Each ofthe double sheet metal elements 100 comprises a first and second sheetmetal end section 102, 104 that are arranged on top of one another. Inthe case of the double sheet metal element 100 shown in FIG. 1A, an edge106 of the double sheet metal element 100 is provided by the secondsheet metal end section 104 or by the edge thereof. In the case of thedouble sheet metal element 100 shown in FIG. 1B, an edge 106 of thedouble sheet metal element 100 is provided by the first sheet metal endsection 102 or by the edge thereof. FIG. 1C finally shows an embodimentof the double sheet metal element 100 in which the edge 106 of thedouble sheet metal element 100 is provided by both sheet metal endsections 102, 104 or by the edges thereof.

FIGS. 2A and 2B show exemplary double sheet metal elements 100. FIG. 2Ashows a double sheet metal element 100 in which the two sheet metal endsections 102, 104 are end sections of two different sheets 108, 110. Forexample, each of the two sheets 108, 110 is a half shell element, thatis, a respective curved sheet metal section adjoins the two sheet metalend sections 102, 104. Arranged on top of one another, the half shellelements create a hollow space for receiving additional structures, suchas insulating material and/or catalytic converter elements. FIG. 2Bshows a double sheet metal element 100 in which the two sheet metal endsections 102, 104 are different end sections of one sheet 108. Theshared sheet 108 is rolled in, for example, so that two opposing sheetmetal sections 102, 104 of this sheet 108 end up on top of one another.

FIG. 3 shows, by way of example, a first method for connecting two sheetmetal end sections that are arranged on top of one another by means offorming. In block 200, a double sheet metal element is provided, whichis arranged and fixed in a processing position. The double sheet metalelement comprises two sheet metal end sections arranged on top of oneanother and extends in an extension plane. The two sheet metal endsections are to be connected to one another along a connecting linelocated in the extension plane. In block 202, a first, for exampleV-shaped, depression is introduced into the double sheet metal element,which extends along the connecting line. In block 204, a first foldedsection of the double sheet metal element is created along theconnecting line. In the process, two mutually opposing inside walls ofthe first V-shaped depression are pressed against one another. In block206, a second, for example V-shaped, depression is introduced into thedouble sheet metal element. In block 208, a second folded section of thedouble sheet metal element or connecting section is created along theconnecting line, which includes the first folded section. In theprocess, two mutually opposing inside walls of the second V-shapeddepression are pressed against one another. In block 210, the secondfolded section of the double sheet metal element is aligned. In theprocess, the second folded section is bent about a bending axis providedby an edge of the second V-shaped depression, so that the second foldedsection extends parallel to the extension plane of the double sheetmetal element.

In block 212, a, for example V-shaped, depression extending along theconnecting line is introduced into the double sheet metal element.According to embodiments, the third V-shaped depression is introducedinto the same surface of the double sheet metal element, similarly tothe first and second V-shaped depressions. In block 214, the secondfolded section is perpendicularly oriented relative to the extensionplane of the double sheet metal element. According to embodiments, theperpendicular orientation comprises bending over a portion of the doublesheet metal element which includes the second folded section along abending axis that extends parallel to the connecting line, so that thesecond folded section extends perpendicularly to the extension plane.According to embodiments, an edge of the third V-shaped depressionprovides the bending axis, about which the portion of the double sheetmetal element including the second folded section is bent.

FIGS. 4A to 4K show an exemplary device 120 for carrying out the firstmethod from FIG. 3. FIG. 4A shows a punch 130 comprising a punch element132. The punch element 132 has a, for example, V-shaped cross-section,wherein one leg of the V-shaped cross-section is provided by a firststop surface 134. The punch 130 furthermore comprises a second stopsurface 136. In addition to the punch 130, the device 120 comprises adie 140, which provides a bearing surface for placing on the doublesheet metal element 100. Three, for example V-shaped, cavities 142, 144,146, which are arranged parallel to one another, are introduced into thebearing surface of the die 140. Finally, the device 120 also comprises aclamping device 150 for fixing an end 105 of the double sheet metalelement 100 on the bearing surface of the die 140, while the oppositeend 106 of the double sheet metal element 100 is a free, non-fixed end.In the course of the provision, the double sheet metal element 100 ispositioned in a processing position on the bearing surface, and is fixedusing the clamping device 150. In the shown embodiment, the die 140represents the counter bearing for clamping the double sheet metalelement 100. In alternative embodiments, the clamping device cancomprise an additional clamping element as the counter bearing, inaddition to the clamping element 150. So as to connect the two sheetmetal end sections encompassed by the double sheet metal element 100 bymeans of forming, either the punch 130 can be displaced relative to thedie 140 and/or the die 140 can be displaced, together with the clampingdevice 150, relative to the punch 130.

In FIG. 4B, the punch 130 was displaced vertically from above with thepunch element 132 into the first V-shaped cavity 142, whereby a first,for example V-shaped, depression 160 is introduced into the double sheetmetal element 100. In the process, an edge of the first V-shapeddepression 160 is formed by the edge 106 of the double sheet metalelement 100. In the shown embodiment, the double sheet metal element 100was first fixed in the processing position, using the clamping device150, before the first V-shaped depression 160 is introduced. Accordingto embodiments, the punch 130 includes a third stop surface 190, whichextends parallel to an extension plane 152 of the double sheet metalelement 100, between the first stop surface 134 and the second stopsurface 136. The punch 130 is displaced out of the first V-shaped cavity142 and, as shown in FIG. 4C, is positioned next to the double sheetmetal element 100. Thereafter, the punch 130 is displaced parallel tothe bearing surface of the die 140 against the double sheet metalelement 100, so that the punch 130, with the stop surface 134 of thepunch element 132, presses the first V-shaped depression 160 together,as shown in FIG. 4D. In the process, two mutually opposing inside walls162, 164 of the first V-shaped depression 160 are pressed against oneanother, and a first folded section 166 of the double sheet metalelement 100 is created. The first folded section 166 is a section thatis folded once. The third stop surface 190 prevents one or both of thesheet metal end sections, which at this stage are not yet connected toone another, from being pressed out of the cavity 142 when the twomutually opposing inside walls 162, 164 of the first V-shaped depression160 are pressed against one another. In particular, it is possible forthe third stop surface 190 to prevent the sheet metal end section, ofthe sheet metal end sections that are not yet connected to one another,which is located on top from being pressed out of the cavity 142, whilethe bottom sheet metal end section of the two sheet metal end sectionsthat are not yet connected to one another remains in the cavity 142 andis pressed together by the punch 130.

In FIG. 4E, the punch 130 was displaced vertically from above with thepunch element 132 into the second V-shaped cavity 144, whereby a second,for example V-shaped, depression 170 is introduced into the double sheetmetal element 100. In the process, an inside wall 172 of the secondV-shaped depression 170 is provided by the first folded section 166 andcomprises the edge 106 of the double sheet metal element 100. The punch130 is displaced out of the second V-shaped cavity 144 and, as shown inFIG. 4F, is positioned next to the double sheet metal element 100.Thereafter, the punch 130 is displaced parallel to the bearing surfaceof the die 140 against the double sheet metal element 100, so that thepunch 130, with the stop surface 134 of the punch element 132, pressesthe second V-shaped depression 170 together, as shown in FIG. 4G. In theprocess, two mutually opposing inside walls 172, 174 of the secondV-shaped depression 170 are pressed against one another, and aconnecting section in the form of a second folded section 176 of thedouble sheet metal element 100 is created, which comprises the firstfolded section 166. In other words, the second folded section 176, andthus the connecting section, is a section that is folded twice. In FIG.4H, the second folded section 176 of the double sheet metal element 100was aligned by the punch element 132 having exerted pressure on thesecond folded section 176. The alignment of the second folded section176 comprises bending the second folded section 176 about a bending axisprovided by an edge of the second V-shaped depression 170, so that thesecond folded section 176 extends parallel to the extension plane 152 ofthe double sheet metal element 100.

In FIG. 4I, the punch 130 was displaced vertically from above with thepunch element 132 into the third V-shaped cavity 146, whereby a third,for example V-shaped, depression 180 is introduced into the double sheetmetal element 100. In the process, an inside wall 182 of the thirdV-shaped depression 180 is provided by the second folded section 176 ofthe double sheet metal element 100. The punch 130 is displaced out ofthe third V-shaped cavity 146 and, as shown in FIG. 4J, is positionednext to the double sheet metal element 100. Thereafter, the punch 130 isdisplaced parallel to the bearing surface of the die 140 against thedouble sheet metal element 100, so that the second folded section 176 isperpendicularly oriented relative to the extension plane 152 of thedouble sheet metal element 100 in that the second stop surface 136 ofthe punch 130 presses against the second folded section 176 of thedouble sheet metal element 100. In the process, a portion of the doublesheet metal element 100 comprising the connecting section including thesecond folded section 176 is bent along a bending axis provided by anedge of the third V-shaped depression 180, so that the second foldedsection 176, in the end position thereof shown in FIG. 4K, extendsperpendicularly to the extension plane 152 of the double sheet metalelement 100.

According to alternative embodiments, the connecting section may alsoexclusively consist of the first folded section 166, that is, theconnecting section is a section that is folded once. In this case, thesteps according to FIGS. 4G to 4J can be dispensed with. Following thestep shown in FIG. 4F, the punch 130 is displaced parallel to thebearing surface of the die 140 against the double sheet metal element100, so that the first folded section 166 is perpendicularly orientedrelative to the extension plane 152 of the double sheet metal element100 in that the second stop surface 136 of the punch 130 presses againstthe first folded section 166 of the double sheet metal element 100. Inthe process, a portion of the double sheet metal element 100 comprisingthe connecting section including the first folded section 166 is bentalong a bending axis provided by an edge of the second V-shapeddepression 170, so that the first folded section 166, in an end positionanalogous to the end position of the second folded section 176 shown inFIG. 4K, extends perpendicularly to the extension plane 152 of thedouble sheet metal element 100. The method according to FIG. 6 in thiscase comprises the steps 300 to 304 and 310, wherein the first foldedsection is perpendicularly oriented in step 310.

FIGS. 5A to 5C show exemplary V-shaped depressions 160, which eachinclude two mutually opposing inside walls 162, 164 as well as a base165. In the case of the V-shaped depression 160 shown in FIG. 5A, thebase 165 is formed by a contact line at which the two mutually opposinginside walls 162, 164 meet one another. FIG. 5B shows a V-shapeddepression 160 having a base 165 in the form of an arched surface, andFIG. 5C shows a V-shaped depression 160 having a base 165 in the form ofa planar surface. According to embodiments, the planar surface formingthe base 165 may also be inclined relative to the alignment of theplanar surface shown in FIG. 5C.

FIGS. 5D to 5G show, by way of example, different relative contributionsof the two sheet metal end sections 102, 104, which form the doublesheet metal element 100, based on the V-shaped depression 160 of FIG.5A. The arrangement shown in FIG. 5D results from the embodimentaccording to FIG. 1C in which the edge 106 of the double sheet metalelement 100 is provided by both sheet metal end sections 102, 104 or bythe edges thereof. In other words, the two sheet metal end sections 102,104 in FIG. 1C extend equally far along the shared extension plane. Inthe process, the two mutually opposing inside walls 162, 164 of thedepression 160 are both provided by the first sheet metal end section102.

In the case of the arrangement shown in FIG. 5E, the first sheet metalend section 102 is shorter than the second sheet metal end section 104.The shown arrangement results from the embodiment according to FIG. 1Ain which the edge 106 of the double sheet metal element 100 is providedby the second sheet metal end section 104 or by the edge thereof. Inother words, the second sheet metal end section 104 in FIG. 1A extendsfurther along the shared extension plane than the first sheet metal endsection 102, and protrudes beyond the same. The first inside wall 162 ofthe two mutually opposing inside walls 162, 164 of the depression 160 isprovided by the first sheet metal end section 102, while a first segmentof the second inside wall 162 is provided by the first sheet metal endsection 102, and a second segment of the second inside wall 162 isprovided by the second sheet metal end section 104. More precisely, thesecond segment of the second inside wall 162 is formed by the portion ofthe second sheet metal end section 104 which protrudes beyond the firstsheet metal end section 102. FIG. 5F shows an embodiment in which thesecond sheet metal end section 104 protrudes beyond the first sheetmetal end section 102 so far that the sheet metal end section 102,during the introduction of the V-shaped depression 160, does not extendbeyond the base 165 thereof. In this case, the first inside wall 162 ofthe two mutually opposing inside walls 162, 164 of the depression 160 isprovided by the first sheet metal end section 102, while the secondinside wall 162 is provided by the second sheet metal end section 104.When the V-shaped depression 160 is pressed together in the course ofthe completion of the first folded section, the edge of the first sheetmetal end section 102 is enveloped by the second sheet metal end section104 so as not to be exposed (refer to FIG. 19B).

In the case of the arrangement shown in FIG. 5G, the first sheet metalend section 102 is longer than the second sheet metal end section 104.The shown arrangement results from the embodiment according to FIG. 1Bin which the edge 106 of the double sheet metal element 100 is providedby the first sheet metal end section 102 or by the edge thereof. Inother words, the first sheet metal end section 102 in FIG. 1B extendsfurther along the shared extension plane than the second sheet metal endsection 104, and protrudes beyond the same. In the process, the twomutually opposing inside walls 162, 164 of the depression 160 are bothprovided by the first sheet metal end section 102. However, during theintroduction of the V-shaped depression 160, the second sheet metal endsection 104 extends beyond the base 165, so that it can be ensured, whenthe V-shaped depression 160 is pressed together in the course of thecompletion of the first folded section, that the edge of the secondsheet metal section 104 is folded over. After the first folded sectionhas been oriented perpendicularly to the (original) extension plane ofthe two sheet metal end sections 102, 104, the edge of the second sheetmetal end section 104 is not exposed. In the case of a connectingsection that comprises a second folded section, that is, is foldedtwice, embodiments are possible in which the second sheet metal endsection 104, during the introduction of the V-shaped depression 160,does not extend beyond the base 165 thereof. In this case, it is ensuredin the course of a completion of the second folded section that the edgeof the second sheet metal end section 104 is folded over, and is nolonger exposed.

Based on the embodiments shown in FIGS. 5D to 5G, it is apparent thatdifferently far extensions of the two sheet metal end sections 102, 104are possible, in which the two sheet metal end sections 102, 104 eachextend differently far along the resulting V-shaped depression 160 orcontribute to the creation thereof to different degrees. All embodimentshave in common that they ensure that the edges of both sheet metal endsections 102, 104 are folded over, or the edge of the first sheet metalend section 102 is enveloped by the folded-over second sheet metal endsection 104, when the V-shaped depression 160 is pressed together in thecourse of a completion of the first folded section. After the first, orpossibly second, folded section has been oriented perpendicularly to the(original) extension plane of the two sheet metal end sections 102, 104,neither of the two edges of the sheet metal end sections 102, 104 isexposed any longer.

FIG. 6 shows an exemplary second method for connecting two sheet metalend sections arranged on top of one another by means of forming. Inblock 300, a double sheet metal element is provided, which is arrangedand fixed in a processing position. In block 302, a first, for exampleV-shaped, depression is introduced along a connecting line into a firstsurface of the double sheet metal element, along which the two sheetmetal end sections of the double sheet metal element are to be connectedto one another. In block 304, a first folded section of the double sheetmetal element is created along the connecting line. In the process, twomutually opposing inside walls of the first V-shaped depression arepressed against one another. In block 306, a second, for exampleV-shaped, depression is introduced into the first surface of the doublesheet metal element into which the first V-shaped depression was alreadyintroduced in block 302. Moreover, a third, for example V-shaped,depression extending along the connecting line is introduced into asecond surface of the double sheet metal element which faces away fromthe first surface. For example, the first surface is provided by a topside of the double sheet metal element, while the second surface isprovided by a bottom side of the double sheet metal element, with whichthe double sheet metal element rests on a bearing surface.

In block 308, a second folded section of the double sheet metal elementis created along the connecting line, which includes the first foldedsection. In the process, two mutually opposing inside walls of thesecond V-shaped depression are pressed against one another. In block310, the second folded section is perpendicularly oriented relative tothe extension plane of the double sheet metal element. According toembodiments, the perpendicular orientation comprises bending over aportion of the double sheet metal element which includes the secondfolded section along a bending axis that extends parallel to theconnecting line, so that the second folded section extendsperpendicularly to the extension plane. According to embodiments, thebending axis, about which the portion of the double sheet metal elementthat comprises the second folded section is bent, extends along a baseof the third V-shaped depression.

FIGS. 7A to 7K show an exemplary device 120 for carrying out the secondmethod from FIG. 6. In the process, the involved moving device elementsof the device 120 are displaced exclusively perpendicularly to theextension plane of the double sheet metal element 100. The device 120comprises a punch 130 comprising two punch elements 132, 133. Each ofthe two punch elements 132, 133 has a, for example, V-shapedcross-section, wherein each leg of the V-shaped cross-section isprovided by a first stop surface 134, 135. According to embodiments, thesecond punch element 133 is arranged lower in the vertical direction,that is, perpendicularly to the extension plane 152 of the double sheetmetal element 100. This has the effect that the second punch element 133engaging with the double sheet metal element 100 at the same time avoidsthe first punch element 132 from engaging with the double sheet metalelement 100.

In addition to the punch 130, the device 120 comprises a die 140, whichincludes two sub-dies 141, 143 providing a bearing surface for placingon the double sheet metal element 100. A, for example V-shaped, cavity142, 144 is introduced into each of the sub-dies 141, 143, wherein thetwo V-shaped cavities 142, 144 extend parallel to one another. In theprocess, the sub-die 141 with the V-shaped cavity 142 is arrangedbeneath the first punch element 132, and the sub-die 143 with theV-shaped cavity 144 is arranged beneath the second punch element 133.The sub-die 141 is moreover displaceable relative to the sub-die 143 inthe vertical direction, that is, perpendicularly to the extension plane152 of the double sheet metal element 100. The sub-die 141 furthermoreincludes a second stop surface 136.

Finally, the device 120 also comprises a clamping device for fixing anend 105 of the double sheet metal element 100 by way of a first clampingelement 150 and a second clamping element 151 on a portion of thebearing surface of the sub-dies which is provided by the secand clampingelement 151, while the opposite end 106 of the double sheet metalelement 100 is a free, non-fixed end. So as to connect the two sheetmetal end sections encompassed by the double sheet metal element 100 bymeans of forming, the punch 130 as well as the sub-die 141 aredisplaced, while the positions of the sub-die 143 as well as of theclamping device 150, 151 are held constant. In the course of theprovision, the double sheet metal element 100 is positioned in aprocessing position on the bearing surface and is fixed, using theclamping device including the two clamping elements 150, 151.

In FIG. 7A, the punch 130 was displaced vertically from above with thepunch element 133 into the V-shaped cavity 144 of the sub-die 143,whereby a first, for example V-shaped, depression 160 is introduced intothe double sheet metal element 100. In the process, an edge of the firstV-shaped depression 160 is formed by the edge 106 of the double sheetmetal element 100. As a result of the differing positioning of the twopunch elements 132, 133 at differing heights in the vertical direction,the first punch element 132 does not engage with the double sheet metalelement 100. In the shown embodiment, the double sheet metal element 100was first fixed in the processing position, using the clamping device150 comprising the two clamping elements 150, 151, before the firstV-shaped depression 160 is introduced. According to embodiments, thesecond punch element 133, in addition to a first stop surface 135,includes a further stop surface 191, which extends parallel to anextension plane 152 of the double sheet metal element 100. Likewise,according to embodiments, the first punch element 132 includes a thirdstop surface 190, which is arranged between a first stop surface 134 andthe second stop surface 136 and extends parallel to the extension plane152 of the double sheet metal element 100.

The punch 130 is displaced out of the first V-shaped cavity 144upwardly, as shown in FIG. 7B, into the starting position thereof abovethe sub-dies 141, 143. Thereafter, the sub-die 141 is displaced in thevertical direction upwardly toward the punch 130. In this way, as isshown in FIG. 7C, the free end comprising the edge 106 of the doublesheet metal element 100 and the first V-shaped depression 160 is pivotedupwardly by a first angle αbout the end 105 that is fixed in astationary manner by the clamping device 150, toward the punch 130. As aresult, the first V-shaped depression 160 is positioned in a tiltedmanner beneath the first stop surface 135 of the second punch element133. The punch 130 is displaced downwardly, so that the first stopsurface 135 of the second punch element 133, as shown in FIG. 7D, makescontact with an outside wall of the first V-shaped depression 160. Fromthis point on, the sub-die 141 and the punch 130 are synchronouslydisplaced downwardly until the sub-die 141, as shown in FIG. 7E, hasreached the starting position thereof at the same height as the sub-die143 and the clamping element 151. The punch 130 is displaced with thesecond punch element 133 further downwardly into the V-shaped cavity 144of the sub-die 143, so that the second punch element 133, with the stopsurface 135, presses the first V-shaped depression 160 together. In theprocess, two mutually opposing inside walls 162, 164 of the firstV-shaped depression 160 are pressed against one another, and a firstfolded section 166 of the double sheet metal element 100 is created. Thefirst folded section 166 is a section that is folded once. The furtherstop surface 191 prevents one or both of the sheet metal end sections ofthe double sheet metal element 100, which at this stage are not yetconnected to one another, from being pressed away from the cavity 144 orout of the cavity 144, when the V-shaped depression 160 is pressed downby the first stop surface 135 of the second punch element 133 makingcontact with the outer side and/or when, subsequently, the two mutuallyopposing inside walls 162, 164 of the first V-shaped depression 160 arepressed against one another in the cavity 144. In particular, it ispossible for the further stop surface 191 to prevent the sheet metal endsection, of the sheet metal end sections that are not yet connected toone another, which is located on top from being pressed away from thecavity 144 or out of the cavity 144, while the bottom sheet metal endsection of the two sheet metal end sections that are not yet connectedto one another is pressed into the cavity 144 and is pressed together bythe second punch element 133.

The punch 130 is displaced upwardly out of the V-shaped cavity 142, asshown in FIG. 7F, into the starting position thereof above the sub-dies141, 143. Thereafter, the sub-die 141 is displaced in the verticaldirection upwardly toward the punch 130. In this way, as is shown inFIG. 7G, the free end comprising the edge 106 of the double sheet metalelement 100 and the first folded section 166 is pivoted upwardly by asecond angle αbout the end 105 that is fixed in a stationary manner bythe clamping device 150, toward the punch 130. This causes the firstfolded section 166 of the double sheet metal element 100 to be arrangedbetween the first and second punch elements 132, 133. In the process, noportion of the double sheet metal element 100 is present any longerbeneath the second punch element 133. In FIG. 7H, the punch 130 wasdisplaced perpendicularly downwardly with the first punch element 132into the V-shaped cavity 142 of the sub-die 141, whereby a second, forexample V-shaped, depression 170 is introduced into the double sheetmetal element 100. Since the sub-die 141 is located in an elevatedposition relative to the sub-die 143 and the clamping element 151, athird, for example V-shaped, depression 180 is synchronously introducedinto the double sheet metal element 100, parallel to the second V-shapeddepression 170. The first two V-shaped depressions 160, 170 areintroduced into a first surface of the double sheet metal element 100which faces the punch 130, while the third V-shaped depression 180 isintroduced into a second surface of the double sheet metal element 100which faces away from the first surface. This second surface of thedouble sheet metal element 100 faces the sub-dies 141, 143.

Thereafter, the punch 130 is displaced upwardly into the startingposition thereof, and the sub-die 141 is displaced slightly furtherupwardly. In this way, the free end of the double sheet metal element100, including the second V-shaped depression 170, is raised and tiltedabout the fixed end 105 of the double sheet metal element 100. The punch130 is displaced downwardly with the first punch element 132 into theV-shaped cavity 142 of the sub-die 141, so that the second stop surface136 of the first punch element 132, as shown in FIG. 7I, makes contactwith an outside wall of the second V-shaped depression 170 and pressesthe second V-shaped depression 170 together. In the process, twomutually opposing inside walls of the second V-shaped depression 170 arepressed against one another, and a connecting section in the form of asecond folded section 176 of the double sheet metal element 100 iscreated. In other words, the second folded section 176, and thus theconnecting section, is a section that is folded twice, which encompassesthe first folded section 166.

Thereafter, the punch 130 is displaced upwardly into the startingposition thereof, as shown in FIG. 7J. The sub-die 141 is displacedfurther upwardly, whereby the connecting section comprising the secondfolded section 176 is perpendicularly oriented relative to the extensionplane 152 of the double sheet metal element 100. In the process, thesecond stop surface 136 of the sub-die 141 presses against the secondfolded section 176 of the double sheet metal element 100, which is bentabout a bending axis provided by an edge of the third V-shapeddepression 180. As a result, a portion of the double sheet metal element100 comprising the connecting section is then bent upwardly, so that, inthe end position shown in FIG. 7K, the connecting section comprising thesecond folded section 176 extends perpendicularly to the extension plane152 of the double sheet metal element 100.

FIG. 8 shows, by way of example, a third method for connecting two sheetmetal end sections arranged on top of one another by means of forming.In block 400, a double sheet metal element is provided. In block 402, afirst, for example V-shaped, depression is introduced along a connectingline into the double sheet metal element, along which the two sheetmetal end sections of the double sheet metal element are to be connectedto one another. In block 404, a first folded section of the double sheetmetal element is created along the connecting line. In the process, twomutually opposing inside walls of the first V-shaped depression arepressed against one another. In block 406, the first folded section ofthe double sheet metal element is aligned. In the process, the firstfolded section is bent about a bending axis provided by an edge of thefirst V-shaped depression, so that the first folded section extendsparallel to the extension plane of the double sheet metal element. Inblock 408, a second, for example V-shaped, depression is introduced intothe double sheet metal element. In block 410, a second folded section ofthe double sheet metal element is created along the connecting line,which includes the first folded section. In the process, two mutuallyopposing inside walls of the second V-shaped depression are pressedagainst one another. In block 412, the connecting section comprising thesecond folded section of the double sheet metal element is aligned. Inthe process, the second folded section is bent about a bending axisprovided by an edge of the second V-shaped depression, so that thesecond folded section extends parallel to the extension plane of thedouble sheet metal element. In block 414, the connecting sectioncomprising the second folded section is perpendicularly orientedrelative to the extension plane of the double sheet metal element.According to embodiments, the perpendicular orientation comprisesbending over a portion of the double sheet metal element comprising theconnecting section along a bending axis extending parallel to theconnecting line, so that the connecting section comprising the secondfolded section extends perpendicularly to the extension plane.

FIGS. 9A and 9B show an exemplary device 500 for carrying out the thirdmethod from FIG. 8. FIG. 9A shows a top view from above onto the device500. FIG. 9B shows a side view of the device 500. FIGS. 10A to 10G showexemplary elements of the device 500 from FIGS. 9A and 9B. The device500 comprises seven roller pairs 510, 520, 530, 540, 550, 560, 570,which are arranged in row behind one another. In the process, the rollerpair 510 geometrically essentially corresponds to the roller pair 540,the roller pair 520 corresponds to the roller pair 550, and the rollerpair 530 corresponds to roller pair 560. The double sheet metal element100 is guided along the device 500, consecutively passing through theindividual roller pairs 510, 520, 530, 540, 550, 560, 570. The firstroller pair 510, which is shown in greater detail in FIG. 10A,introduces a first, for example V-shaped, depression into the doublesheet metal element 100. For this purpose, a first roller 512 of theroller pair 510 includes a circumferential, for example V-shaped, cavityin the circumferential or running surface thereof. A second roller 514of the roller pair 510 includes a circumferential, for example V-shaped,elevation on the circumferential or running surface thereof. A firstfolded section of the double sheet metal element 100 is created by thesecond roller pair 520, which is shown in greater detail in FIG. 10B,wherein two mutually opposing inside walls of the first V-shapeddepression are pressed against one another. The first roller 512 sharesthe second roller pair 520 with the first roller pair 510. A secondroller 524 of the roller pair 520 includes a circumferential V-shapedelevation on the circumferential or running surface thereof, wherein theorientation of the second roller 524 is tilted about an axis of rotationsituated perpendicularly on the extension direction of the double sheetmetal element 100. The first folded section of the double sheet metalelement 100 is aligned by the third roller pair 530, which is shown ingreater detail in FIG. 10C, so that the first folded section extendsparallel to the extension plane of the double sheet metal element 100.For this purpose, the two rollers 532, 534 of the third roller pair 530include planar circumferential or running surfaces that are parallel inthe axial direction.

The fourth roller pair 540 shown in greater detail in FIG. 10D has thesame geometry as the first roller pair 510 and is used to introduce asecond, for example V-shaped, depression into the double sheet metalelement 100. The fifth roller pair 550 shown in greater detail in FIG.10E has the same geometry as the second roller pair 520 and is used tocreate a second folded section of the double sheet metal element 100 orconnecting section. The sixth roller pair 560 shown in greater detail inFIG. 10F has the same geometry as the third roller pair 530 and is usedto align the second folded section with respect to the extension planeof the double sheet metal element 100.

The seventh roller pair 570, which is shown in greater detail in FIG.10G, comprises two rollers 572, 574, which each provide a stop surfacebetween which the connecting section comprising the second foldedsection is guided out of the alignment thereof, which is parallel to theextension plane of the double sheet metal element 100, into aperpendicularly oriented alignment. As a result, the connecting sectioncomprising the second folded section extends perpendicularly to theextension plane of the double sheet metal element 100, after havingpassed through the seventh roller pair 570.

FIGS. 11A to 11C show an alternative selection and arrangement ofexemplary elements of the device 500 from FIGS. 9A and 9B. The selectionaccording to FIGS. 11A to 11C comprises four, instead of the seven,roller pairs of the device 500. In contrast to the device 500, theroller pairs of FIGS. 11A to 11C are not arranged in a stationary mannerin a row. Rather, the roller pairs 510, 520, 530, 570 are displacedindividually or in groups, once or multiple times, along an edge of thedouble sheet metal element 100 so as to establish the connection betweenthe sheet metal end sections of the double sheet metal element. Forexample, the roller pairs 510, 520, 530 are arranged in a group. Insteadof the additional roller pairs 540, 550, 560 of the device 500, rather,the roller pairs 510, 520, 530 are used twice, as is shown in FIGS. 11Aand 11B. For this purpose, for example, the group comprising the rollerpairs 510, 520, 530 is displaced twice along the edge of the doublesheet metal element 100. For example, the group is displaced from astarting position into an end position along the edge of the doublesheet metal element 100, whereby a first folded section is created alongthe edge of the double sheet metal element 100. Thereafter, the group isreturned to the starting position and displaced from a starting positioninto an end position along the first folded section, whereby a secondfolded section is created. The perpendicular orientation of theresulting connecting section comprising the second folded section iscarried out using the roller pair 570, which is subsequently displacedfrom the starting position into the end position along the second foldedsection.

According to alternative embodiments, the connecting section onlycomprises the first folded section. In other words, the group comprisingthe roller pairs 510, 520, 530 is only displaced once along the edge ofthe double sheet metal element 100, as is shown in FIG. 11A, andthereafter the perpendicular orientation according to FIG. 11C iscarried out using the roller pair 570. The method according to FIG. 8 inthis case comprises the steps 400 to 406 and 414, wherein the firstfolded section is perpendicularly oriented in step 414.

FIGS. 12A and 12B show schematic diagrams of two exemplary embodimentsof double sheet metal elements 100 including recesses 600. FIG. 12Ashows a double sheet metal element 100 having a convexly curved bendingaxis 604, along which the connecting section is to be perpendicularlyoriented after folding. For example, the edge 106 of the double sheetmetal element 100 extends parallel to the convexly curved bending axis604. Recesses 600 extend between the bending axis 604 and the edge 106,for example at regular intervals along the bending axis 604. Therecesses 600 have a width 601, which increases with increasing distancefrom the bending axis 604. According to embodiments, the width 601 isselected so as to compensate for the difference between the arc lengthof the bending axis 604 and the arc length of the section of the doublesheet metal element 100 that is to be folded and perpendicularlyoriented, which increases with increasing distance from the bending axis604. When the folded sections are created and the connecting section issubsequently perpendicularly oriented, so as to extend perpendicularlyto the extension plane of the double sheet metal element, according toembodiments the recesses are closed as a result of the perpendicularorientation, and the perpendicularly oriented connecting section 602 hasa constant arc length over the distance from the bending axis 604, whichis identical to the arc length of the bending axis 604 or only has anegligible deviation. According to embodiments, each of the recesses 600has a V shape.

FIG. 12B shows a double sheet metal element 100 having a concavelycurved bending axis 604, along which the connecting section is to beperpendicularly oriented after folding. In this case, the arc lengthdecreases with increasing distance from the bending axis 604. When theconnecting section is perpendicularly oriented, it must be adapted tothe larger arc length of the bending axis 604. Such an adaptation can beimplemented by recesses 600, which diverge further as a result of theperpendicular orientation of the connecting section and therebycompensate for the difference in the arc lengths. According toembodiments, the width 601 of the recesses 600 is selected to beconstant, but increases with increasing distance from the bending axis604 due to the perpendicular orientation of the connecting section.According to embodiments, the recesses 600 are linear notches.

FIGS. 13A and 13B show exemplary embodiments of two double sheet metalelements 100 having a corrugated structure 606. Embodiments can have theadvantage that an alternative method for compensating for different arclengths in the case of a convexly curved bending axis 604, as is shownin FIG. 13A, is provided. FIG. 13A shows a top view perpendicularly fromabove onto a double sheet metal element 100. The connecting section 602is perpendicularly oriented so as to extend substantiallyperpendicularly with respect to the extension plane of the double sheetmetal element 100. The perpendicularly oriented connecting section 602has a corrugated structure 606 including a plurality of additionaldepressions, the depth of which increases with increasing distance fromthe bending axis 604, that is, perpendicularly to the extension plane ofthe double sheet metal element 100. As a result of the corrugatedstructure 606, material of the connecting section 602, which has becomesuperfluous due to the shortening of the arc length of the connectingsection caused by the perpendicular orientation, can be distributed inthe direction parallel to the extension plane of the double sheet metalelement 100. In addition, embodiments can have the advantage that thestability of the connecting section, and thus of the connection, can beincreased by the corrugated structure 606.

FIG. 13B shows a top view perpendicularly from above onto a double sheetmetal element 100 having a straight bending axis 604. In this case, thecorrugated structure 606 is solely used to additionally stabilize theconnecting section 602, and thus the connection itself. According toembodiments, the straight bending axis 604 is maintained, and thecorrugated structure 606 is only introduced into the connecting section602 by way of material expansion. According to alternative embodiments,the corrugated structure 606 also includes the bending axis 604. Forexample, the connecting section 602 is perpendicularly oriented, andthereafter the corrugated structure 606 is introduced.

FIGS. 14A to 14C show schematic diagrams of exemplary embodiments of anembossing tool 700. FIG. 14A shows a perspective view of an exemplaryembossing tool 700. The embossing tool 700 comprises an upper and alower part 702, 704. The shown embossing tool 700 is configured tointroduce a corrugated structure 606 into a convexly curved connectingsection, as is shown in FIG. 13A, for example. The lower part 704 of theembossing tool 700 includes a concave curved embossing surface 706,which is designed to complement the convexly curved connecting sectionhaving the corrugated structure 606 and serves as a negative mold forembossing the corrugated structure 606. FIGS. 14B and 14C show furtherperspective views of the lower part 704 of the embossing tool 700.

FIG. 15 shows a schematic flow chart of an exemplary embodiment of afourth method for connecting two sheet metal end sections that arearranged on top of one another by means of forming. In block 800, adouble sheet metal element is provided. The double sheet metal elementcomprises two sheet metal end sections arranged on top of one anotherand extends in an extension plane. The two sheet metal end sections areto be connected to one another along a connecting line located in theextension plane. In block 802, a first depression, for example V-shapeddepression, is introduced into the double sheet metal element, whichextends along the connecting line. By introducing the first depression,the double sheet metal element is brought into a processing position.While a device for introducing the first depression, for example apunch, is engaged with the double sheet metal element and holds ittemporarily in the processing position, the double sheet metal elementis fixed, in block 804, in the processing position for furtherprocessing, using a clamping device.

In block 806, a first folded section of the double sheet metal elementis created along the connecting line. In the process, two mutuallyopposing inside walls of the first depression are pressed against oneanother. The resulting first folded section is a section that is foldedonce. In block 808, a second depression, for example a V-shapeddepression, is introduced into the double sheet metal element. In block810, a second folded section of the double sheet metal element iscreated along the connecting line, which includes the first foldedsection. In the process, two mutually opposing inside walls of thesecond depression are pressed against one another. The resulting secondfolded section is a section that is folded twice. In block 812, theconnecting section thus created comprising the second folded section isperpendicularly oriented relative to the extension plane of the doublesheet metal element. According to embodiments, the perpendicularorientation comprises bending over a portion of the double sheet metalelement comprising the connecting section including the second foldedsection along a bending axis that extends parallel to the connectingline, so that the connecting section extends perpendicularly to theextension plane.

According to alternative embodiments, the connecting section can beimplemented by the first folded section, without a second folded sectionbeing created according to blocks 808, 810. In a procedure correspondingto block 812, the connecting section thus created comprising the firstfolded section is perpendicularly oriented relative to the extensionplane of the double sheet metal element. According to embodiments, theperpendicular orientation comprises bending over a portion of the doublesheet metal element comprising the connecting section including thefirst folded section along a bending axis that extends parallel to theconnecting line, so that the connecting section extends perpendicularlyto the extension plane.

FIGS. 16A to 161 show schematic diagrams of an exemplary embodiment of adevice 120 for carrying out the fourth method from FIG. 15. In theprocess, the involved moving device elements of the device 120 aredisplaced exclusively perpendicularly to the extension plane of thedouble sheet metal element 100. The device 120 comprises a punch 130comprising a punch element 132. The punch element 132 has a, forexample, V-shaped cross-section, wherein one leg of the V-shapedcross-section is provided by a first stop surface 134. In addition tothe punch 130, the device 120 comprises a die 140, providing a bearingsurface for placing on the double sheet metal element 100. Two, forexample V-shaped, cavities 142, 144 are introduced into the die 140,wherein the two V-shaped cavities 142, 144 extend parallel to oneanother. Both the punch and the die 140 are displaceable in the verticaldirection, that is, perpendicularly to the extension plane 152 of thedouble sheet metal element 100.

Finally, the device 120 also comprises a clamping device for fixing anend 105 of the double sheet metal element 100 by way of a first and asecond clamping element 150, 151, wherein the second clamping element151 provides a portion of the bearing surface for the double sheet metalelement 100. An opposite end 106 of the double sheet metal element 100,in contrast, is a free, non-fixed end.

FIG. 16A shows the double sheet metal element 100, which in a startingposition is arranged on a bearing surface provided by the die 140 andthe second clamping element 151. In this starting position, the doublesheet metal element 100 is not fixed on the bearing surface. So as tointroduce a first, for example V-shaped, depression into the doublesheet metal element 100, the punch element 132 of the punch 130 isdisplaced perpendicularly from above into the first cavity 142 of thedie 140. In the process, the punch element 132, as shown in FIG. 16B,engages with the double sheet metal element 100 and pulls the end 105 tobe fixed between the two clamping elements 150, 151. In the process, thedouble sheet metal element 100 is automatically arranged in a processingposition for further processing. So as to fix the double sheet metalelement 100 in this processing position, the first clamping element 150is likewise displaced downwardly, so that the end 105 of the doublesheet metal element 100 to be fixed is clamped between the two clampingelements 150, 151, while the punch element 132 engaged with the doublesheet metal element 100 holds the double sheet metal element 100 inposition. In this way, it can be effectively prevented that the doublesheet metal element 100, in the course of the clamping process, is atleast partially pressed out of the region between the two clampingelement 150, 151 again by horizontal force components directed parallelto the extension lane 152. When the double sheet metal element 100 isfixed in the processing position by the two clamping elements 150, 151,the punch 130 is displaced upwardly again.

In FIG. 16C, the die 140 is displaced in the vertical direction upwardlytoward the punch 130. In this way, the free end comprising the edge 106of the double sheet metal element 100 and the first V-shaped depressionis pivoted upwardly by a first angle αbout the end 105 that is fixed ina stationary manner by the clamping device 150, toward the punch 130. Asa result, the first V-shaped depression 160 is positioned in a tiltedmanner beneath the first stop surface 134 of the punch element 132. Asis shown in FIG. 16D, the punch 130 is displaced downwardly, so that thestop surface 134 of the punch element 132 makes contact with an outsidewall of the first V-shaped depression and presses the first V-shapeddepression 160 together. In the process, two mutually opposing insidewalls of the first V-shaped depression are pressed against one another,and a first folded section of the double sheet metal element 100 iscreated.

As is shown in FIG. 16E, the punch 130 is displaced upwardly in thevertical direction, and additionally in the horizontal direction towardthe first clamping element 150, so that the punch element 132 ispositioned above the second cavity 144. Moreover, the die 140 isdisplaced in the vertical direction upwardly toward the punch 130. Inthis way, the free end comprising the edge 106 of the double sheet metalelement 100 and the first folded section is pivoted upwardly by a secondangle αbout the end 105 that is fixed in a stationary manner by theclamping device 150, toward the punch 130. As a result, the first foldedsection is pivoted out of the cavity 142. As is shown in FIG. 16F, thepunch element 132 is then displaced downwardly in the vertical directioninto the cavity 144, whereby a second, for example V-shaped, depressionis introduced into the double sheet metal element 100. Thereafter, thepunch 130 is displaced upwardly again the vertical direction.

In FIG. 16G, the die 140 is displaced in the vertical direction upwardlytoward the punch 130. In this way, the second V-shaped depression ispivoted upwardly by a third angle about the end 105 that is fixed in astationary manner by the clamping device 150, toward the punch 130. As aresult, the second V-shaped depression is positioned in a tilted mannerbeneath the first stop surface 134 of the punch element 132. As is shownin FIG. 16H, the punch 130 is displaced downwardly, so that the stopsurface 134 of the punch element 132 makes contact with an outside wallof the second V-shaped depression and presses the second V-shapeddepression together. In the process, two mutually opposing inside wallsof the second V-shaped depression are pressed against one another, and aconnecting section of the double sheet metal element 100 comprising asecond folded section is created. In FIG. 16I finally, first the punch130 and then the die 140 are displaced upwardly in the verticaldirection, wherein the connecting section is perpendicularly oriented bya lateral stop surface 136 of the die 140. In the perpendicularlyoriented position, the connecting section extends perpendicularly to theextension plane 152 of the double sheet metal section.

According to an alternative embodiment, the starting situation shown inFIG. 16A is followed by a method that comprises the steps shown in FIGS.16F to 161. In this case, the folded section generated in FIGS. 16F to16H is a first folded section, that is, a section that is folded onceand forms the connecting section. As is shown in FIG. 16I, theconnecting section is then oriented perpendicularly with respect to theextension plane 152. In this example, the first cavity 142 in the die140 can be dispensed with. The method according to FIG. 15 in this casecomprises the steps 800 to 806 and 812, wherein the first folded sectionis perpendicularly oriented in step 812.

FIGS. 17A and 17B show schematic diagrams of an exemplary embodiment ofsheet metal end sections. FIG. 17A in detail shows the situation priorto the two sheets 108 and 110 being clamped together by the clampingdevice 150, 151 of FIGS. 16A to 161. The two sheets 108 and 110 includean angle α₁, which is small as a result of the small curvature. Theangle α₁ increases with increasing distance from the edge 106 of thedouble sheet metal element 100. According to embodiments, the smallangle α₁ is necessary to avoid damage during the creation of thegeometry of the two sheets 108, 100. When the double sheet metal elementis pulled between the clamping elements 150, 151 by the section Δ as aresult of the introduction of the first depression, the opening betweenthe two sheets 108, 110 is closed in the course of the clamping processin the region of the section Δ. The angle α₂ shown in FIG. 17B andadjoining the closed region is greater than the closed angle α₁. Due tothe relative small angle α₁, the distance between the two sheets 108,110 is relatively small in the region of the section Δ, so that itgenerally cannot be used to receive additional structures that areintroduced into the hollow space enclosed between the sheets 108, 110.The usable hollow space between the sheets 108, 110 is not reduced byclosing this region. However, the double sheet metal element 100 can befolded in such a way that the distance between the resulting connectingsection and the usable hollow space is solely defined by the width ofthe clamping surfaces of the clamping device and encompasses the closedsection Δ, instead of the section Δ remaining in addition to the widthof the clamping surfaces.

FIG. 18 shows a cross-section of an exemplary embodiment of a sheet 108designed as a half shell element. For example, this half shell elementis formed from a planar sheet by way of deep drawing, using a positivemold. This half shell element has an open hollow space 109, which,together with a second half shell element, can create a closed hollowspace for receiving additional structures. So as to avoid damage to thesheet 108 in the course of the deep drawing process, the sheet,proceeding from the edge 106, initially has only a small curvature.During the creation of a closed hollow space, the resulting hollowspace, refer to FIG. 17A, however, is generally so narrow in the regionof the small curvature that it cannot be used to receive additionalstructures. In other words, this is lost space. If, however, this spaceis closed as shown above proceeding from FIG. 17A, so that only asection having a large curvature as shown in FIG. 17B remains, theexpansion of mutually connected half shell elements parallel to theextension plane can be effectively reduced, without reducing the spaceusable for receiving additional structures. This can in particular be ofadvantage when the mutually connected half shell elements are to bearranged or used when space constraints exist.

For the different embodiments of the V depression 160 of FIGS. 5A to 5C,FIGS. 19A to 19F each show exemplary embodiments of the first foldedsection 166 resulting from those embodiments. The embodiments shown inFIGS. 19A, 19C, and 19E differ compared to the embodiments shown inFIGS. 19B, 19D, and 19E in that the two sheet metal end sections 102,104 in the first case have the same length, and in the second case havediffering lengths. The embodiment of FIG. 19A results from the V-shapeddepression 160 of FIG. 5D being pressed together in the course of thecompletion of the first folded section 166. The embodiment of FIG. 19Bresults from the V-shaped depression 160 of FIG. 5F being pressedtogether in the course of the completion of the first folded section166. In this case, the first sheet metal end section 102 is shortercompared to the second sheet metal end section 104 by so much that, eventhough the first sheet metal end section 102 is not folded over with thesecond sheet metal end section 104, the edge of the first sheet metalend section 102 is enveloped by the folded-over sheet metal end section104. FIGS. 19C and 19D, and FIGS. 19E and 19F, each show two situationsanalogous to FIGS. 19A and 19B, which only differ in the shape of thebase 165 of the V-shaped depression 160 from which they result. In thecase of FIGS. 19C and 19D, the base 165 is formed by an arched surface,and in the case of FIGS. 19E and 19F, it is formed by a planar surface.The relationships between the relative extension of the two sheet metalend sections 102, 104 and the contribution thereof to the creation ofthe depression 160 described here apply analogously to arbitraryconfigurations of the depression 160.

LIST OF REFERENCE NUMERALS

-   -   100 double sheet metal element    -   102 sheet metal end section    -   104 sheet metal end section    -   105 fixed end    -   106 edge/free end    -   108 sheet    -   109 hollow space    -   110 sheet    -   120 device    -   130 punch    -   132 punch element    -   133 punch element    -   134 stop surface    -   135 stop surface    -   136 stop surface    -   140 die    -   141 sub-die    -   142 cavity    -   143 sub-die    -   144 cavity    -   146 cavity    -   150 clamping device    -   151 clamping device    -   152 extension plane    -   160 depression    -   162 inside wall    -   164 inside wall    -   165 base    -   166 folded section    -   170 depression    -   172 inside wall    -   174 inside wall    -   176 folded section    -   180 depression    -   190 stop surface    -   191 stop surface    -   510 roller pair    -   512 roller    -   514 roller    -   520 roller pair    -   524 roller    -   530 roller pair    -   532 roller    -   534 roller    -   540 roller pair    -   542 roller    -   544 roller    -   550 roller pair    -   554 roller    -   560 roller pair    -   562 roller    -   564 roller    -   570 roller pair    -   572 roller    -   574 roller    -   600 recess    -   601 width    -   602 connecting section    -   604 bending axis    -   606 corrugated structure    -   607 depth    -   700 embossing tool    -   702 top part    -   704 bottom part    -   706 embossing surface

1.-30. (canceled)
 31. A method for connecting two sheet metal end sections that are arranged on top of one another by means of forming, the method comprising: providing a double sheet metal element, which comprises the two sheet metal end sections that are arranged on top of one another and extends in an extension plane, wherein the two sheet metal end sections are to be connected to one another along a connecting line located in the extension plane; creating a connecting section along the connecting line, the creation of the connecting section comprising: introducing a first depression, which extends along the connecting line, into the double sheet metal element, creating a first folded section of the double sheet metal element along the connecting line, wherein two mutually opposing inside walls of the first depression are pressed against one another; and perpendicularly orienting the connecting section relative to the extension plane of the double sheet metal element by bending over a portion of the double sheet metal element comprising the connecting section along a first bending axis that extends parallel to the connecting line, so that the connecting section extends perpendicularly to the extension plane.
 32. The method according to claim 31, wherein an edge of the first depression is formed by an edge of the double sheet metal element.
 33. The method according to claim 31, wherein prior to the perpendicular orientation of the connecting section, the method comprises aligning the connecting section, the alignment of the connecting section comprising bending the connecting section about a second bending axis extending parallel to the connecting line so that the connecting section extends parallel to the extension plane of the double sheet metal element.
 34. The method according to claim 31, wherein the creation of the connecting section furthermore comprises: introducing a second depression, which extends along the connecting line, into the double sheet metal element; and creating a second folded section of the double sheet metal element along the connecting line, wherein two mutually opposing inside walls of the second depression are pressed against one another, and the second folded section comprises the first folded section.
 35. The method according to claim 34, wherein a first of the two mutually opposing inside walls of the second depression is at least partially provided by the first folded section.
 36. The method according to claim 35, wherein the first of the two mutually opposing inside walls of the second depression comprises the edge of the double sheet metal element
 37. The method according to claim 34, wherein the first and second depressions are both introduced into a first surface of the double sheet metal element.
 38. The method according to claim 37, wherein the creation of the connecting section furthermore comprises introducing a third depression extending along the connecting line into a second surface of the double sheet metal element which faces away from the first surface, the first bending axis extending along a base of the third depression.
 39. The method according to claim 37, wherein the creation of the connecting section furthermore comprises introducing a fourth depression extending along the connecting line into the first surface of the double sheet metal element, an edge of the fourth depression providing the first bending axis.
 40. The method according to claim 34, wherein, prior to the introduction of the second depression, the creation of the connecting section furthermore comprises aligning the first folded section, the alignment of the first folded section comprising bending the first folded section about a third bending axis provided by an edge of the first depression, so that the first folded section extends parallel to the extension plane of the double sheet metal element.
 41. The method according to claim 31, wherein the first, second, third and/or fourth depressions are V-shaped depressions.
 42. The method according to claim 31, wherein the method furthermore comprises positioning and fixing the double sheet metal element in a processing position, the positioning of the double sheet metal element in the processing position being carried out by the introduction of the first depression by means of a device engaging with the double sheet metal element, the fixation of the double sheet metal element in the processing position being carried out using a clamping device, and the double sheet metal element during clamping of the double sheet metal element by means of the clamping device being held in the processing position by the device having engaged with the double sheet metal element.
 43. The method according to claim 31, wherein the method furthermore comprises introducing a corrugated structure having a plurality of additional depressions into the connecting section, the additional depressions, in the perpendicularly oriented state of the connecting section, extending perpendicularly to the extension plane.
 44. The method according to claim 43, wherein the additional depressions each have a depth that increases with increasing distance from the extension plane.
 45. The method according to claim 31, wherein the method furthermore comprises introducing a plurality of recesses into the double sheet metal element along the first bending axis, each of the recesses extending from the first bending axis to the edge of the double sheet metal element.
 46. The method according to claim 45, wherein each of the recesses has a width that increases with increasing distance from the bending axis.
 47. A device, comprising means for connecting two sheet metal end sections that are arranged on top of one another by means of forming, wherein a double sheet metal element comprises the two sheet metal end sections arranged on top of one another and extending in an extension plane, and the two sheet metal end sections are to be connected to one another along a connecting line located in the extension plane, the means of the device for creating a connecting section along the connecting line comprising means for: introducing a first depression, which extends along the connecting line, into the double sheet metal element; and creating a first folded section of the double sheet metal element along the connecting line, wherein two mutually opposing inside walls of the first depression are pressed against one another; the means of the device furthermore comprising means for perpendicularly orienting the connecting section relative to the extension plane of the double sheet metal element by bending over a portion of the double sheet metal element comprising the connecting section along a first bending axis that extends parallel to the connecting line, so that the connecting section extends perpendicularly to the extension plane.
 48. The device according to claim 47, wherein the means of the device comprise a plurality of roller pairs, which carry out the individual steps of connecting.
 49. The device according to claim 48, wherein the roller pairs are arranged in a row behind one another, the double sheet metal element being displaced along the row of roller pairs consecutively passing through the individual roller pairs along the connecting line.
 50. The device according to claim 48, wherein the device is configured to displace the roller pairs in a path-controlled manner along an edge of the double sheet metal element.
 51. The device according to claim 50, wherein a plurality of the steps of connecting are carried out by the same roller pair.
 52. The device according to claim 47, wherein the means of the device for connecting the two sheet metal end sections arranged on top of one another comprise a punch and a die, the punch comprising one or more punch elements extending in a longitudinal direction; the die comprising a bearing surface for placing on the double sheet metal element, including a plurality of cavities, which extend parallel to one another along the longitudinal direction of the punch elements and are each configured to introduce at least one of the depressions into the double sheet metal element; and the punch being configured to be displaced vertically in a first direction into one of the cavities by way of one of the punch elements for introducing the depressions.
 53. The device according to claim 52, wherein the punch is furthermore configured to be displaced in a second direction parallel to the bearing surface, and perpendicularly to the first direction, by way of one of the punch elements against the double sheet metal element, for creating one of the folded sections and/or for perpendicularly orienting the connecting section.
 54. The device according to claim 52, wherein the punch is furthermore configured to be vertically displaced in the first direction into one of the cavities by way of one of the punch elements, for creating one of the folded sections.
 55. The device according to claim 52, wherein the die is configured to be displaced in a direction that is opposite the first direction for introducing one of the depressions, for creating one of the folded sections and/or for perpendicularly orienting the connecting section.
 56. The device according to claim 52, wherein the die comprises a plurality of sub-dies, the sub-dies together providing the bearing surface for placing on the double sheet metal element, each of the sub-dies including at least one of the cavities; and at least one of the sub-dies being configured to be displaced in the direction that is opposite the first direction for introducing one of the depressions, for creating one of the folded sections and/or for perpendicularly orienting the connecting section.
 57. The device according to claim 52, wherein one or more of the cavities are V-shaped cavities.
 58. The device according to claim 52, wherein the device furthermore comprises a clamping device for fixing the double sheet metal element in a processing position.
 59. The device according to 47, wherein the device furthermore comprises an embossing element having a corrugated surface, which is configured to introduce a corrugated structure having a plurality of additional depressions into the connecting section, the additional depressions, in the perpendicularly oriented state of the connecting section, extending perpendicularly to the extension plane.
 60. The device according to claim 47 wherein the device furthermore comprises a cutting device, which is configured to introduce recesses into the double sheet metal element along the first bending axis, each of the recesses extending from the first bending axis to the edge of the double sheet metal element. 